Not Applicable
Not Applicable
The present invention relates to insect control and specifically to insect control mats, typically for use with heaters.
Insect control mats for use with heaters or moving air are well known in the art. The mats are typically made of absorbent, heat-resistive materials. They are treated with insect control active materials and are then placed on heaters of various sorts or in blower devices. The active ingredients are chosen to be such that an effective amount of insect control is achieved by release of the insect control active materials under the heat or moving air use conditions.
It is known that children, pets, and the like will sometimes chew or ingest non-food items. Insect control mats appear not to have caused toxicity problems around children or pets, perhaps because of relatively low concentrations of insect control active materials, the generally non-inviting appearance of the mats or the heaters, or for other reasons. However, new uses for mats, especially for outdoor insect control, have led to the introduction of mats having high amounts of active ingredients, amounts sufficiently high that a child or animal could suffer undesirable effects if such a mat were eaten. Furthermore, such mats are sometimes intend for use in attractive devices that are more likely to be placed on table tops and in other areas where a child""s interest might be sparked.
It can therefore be seen that there is a newly important need for an improved insect control mat made to discourage children or animals from keeping the mat in their mouths.
The following definitions apply throughout. An xe2x80x9caversion materialxe2x80x9d is a chemical or mixture of chemicals, whether synthetic or naturally occurring, that, when present in or on a substance in non-toxic amounts, will cause a person to avoid retaining the substance in the person""s mouth. A xe2x80x9cnon-toxic amountxe2x80x9d of a material is defined as an amount that can be held in a person""s mouth and then expelled without a negative effect on the health of the person. A xe2x80x9cbittering agentxe2x80x9d is an aversion material that causes a repellingly bitter taste when placed in the mouth in non-toxic amounts. A xe2x80x9cspicy repellentxe2x80x9d is an aversion material other than a bittering agent that causes a repelling heat, spicy pain, or revolting taste when placed in the mouth in non-toxic amounts.
xe2x80x9cInsectxe2x80x9d means actual insects and also arthropods and other small animals commonly controlled by the same means used to control insects. An xe2x80x9cinsect control active materialxe2x80x9d is an insecticide, an insect repellent, or other material that causes modifications in insect behavior or development. An insect control active material is xe2x80x9cvolatilexe2x80x9d if it evaporates in effective amounts under the intended conditions of use, the parameters of such conditions of use including but not limited to temperature and air flow. An xe2x80x9cinsect control matxe2x80x9d is a substrate of a selected material that bears or incorporates a volatile insect control material. Insect control mats are commonly available for use with heaters of various sorts and are impregnated with or otherwise contain or support an insect control material that is driven off by heat or moving air in amounts effective to repel or otherwise control flying insects. An amount of a material is an xe2x80x9ceffective amountxe2x80x9d if it is sufficient to have the intended effect. An insect control material will be understood as being xe2x80x9ctoxicxe2x80x9d if it causes undesirable symptoms in a person or domestic animal when consumed in the amount present in an insect control mat. xe2x80x9cUndesirable symptomsxe2x80x9d can include but are not limited to merely unpleasant sensations.
The invention provides an improved insect control mat that includes a heatable substrate, an insect control active material, and an aversion material in an amount effective to cause a person to avoid retaining the mat in the person""s mouth. Preferably, the aversion material is selected from the group consisting of bittering agents, spicy repellents, and combinations thereof. More preferably, the aversion material is selected from the group consisting of denatonium benzoate, denatonium saccharide, denatonium chloride, sucrose benzoate, quinine, quinine hydrochloride, quinine sulfate, brucine, brucine sulfate, quassia, naringin, limonin, phenylthrocarbamide, quebracho, sucrose octaacetate, quassin, quercetin, berberine, and combinations thereof For reasons of cost and effectiveness, denatonium benzoate is the most preferred aversion material.
Many parents would prefer, if only to be very conservative, that their children not ingest insect control materials from insect mats, even in quantities that in fact will do no harm. Although the invention therefore is beneficial even with amounts of insect control active ingredient insufficient actually to be toxic to the average person, the invention is most beneficial when the insect control active ingredient is present in an amount sufficient to be toxic if ingested by a human or domestic animal. For example, the insect control active material d-allethrin (ISO-registered name), is commonly used in insect control mats in amounts of about 50 mg per mat, an amount that appears not to present practical toxicity problems. However, mats prepared for certain uses can contain at least 90 mg of d-allethrin. It is believed to be important that children be deterred from keeping such mats in their mouths.
The insect control active material present in the mat of the invention preferably is selected from the group consisting of d-allethrin, allethrin, prallethrin, bioallethrin, s-bioallethrin, esbiol, dichlorvos, transfluthrin, pyrethrum, and combinations thereof. The insect control active materials just referred to by their ISO registered names are further identified as follows:
All of these materials are of proven effectiveness against insects when used in insect control mats. Particularly preferred insect control active materials are d-allethrin, prallethrin, s-bioallethrin, allethrin, dichlorvos, and combinations thereof, and most preferred is d-allethrin in a total amount greater than or equal to 50 mg. For certain applications, d-allethrin in a total amount greater than or equal to 90 mg is preferred, with an amount greater than or equal to 250 mg being ideal, including amounts as high or higher than 600 mg. The higher amounts of d-allethrin are used in volatile dispensers in which the insect control mat is suspended above the flame of a candle, lamp, or the like, within the chimney of a hurricane lamp-type of device. Preferably the mat is held with an edge of the mat presented toward the flame so that hot gases flow over opposite sides of the mat.
In a preferred embodiment, the heatable substrate of the insect control mat is made of a material selected from the group consisting of matted fibrous materials, ceramic materials, a contained gel, and a polymeric material. When matted fibrous materials are used, a preferred material includes matted cellulosic materials.
In an alternative embodiment, the heatable substrate is a gel that contains the insect control material, the gel being contained within a heat-resistant cup, preferably a cup made of metal or heat-resistant plastic. The gel can be contained within the cup by a volatile-permeable membrane. See e.g. U.S. Pat. No. 5,645,845 for an example of gel-based systems. (The disclosure of this patent and all patents and publications cited herein is incorporated herein by reference as if fully set forth.) A silica gel is preferred, such as that commercially available under the trade name Cabosil.
Alternatively, the heatable substrate can be a polymeric material impregnated with the insect control material. Examples of such polymeric materials are disclosed in European Patent Application No. 94830104.91 (Publication number 0 671 123 A1). Preferred is the block co-polymer comprising an elastomeric polymer and a stiff polymer, such as a polyether-polyamide co-polymer, as disclosed therein
The method of the invention for controlling insects includes the following steps. First, an insect control mat is provided that has a heatable substrate; an insect control active material; and an aversion material in an amount effective to cause a person to avoid retaining the mat in the person""s mouth. Then, the insect control mat is exposed to heat sufficient to release an amount of the insect control material effective to control insects.